Double-tank fuel system.



H. LEMP.

DOUBLE TANK FUEL SYSTEM.

APPLICATION FILED AUG.1, 1904.

Patented May 25, 1909.

Inventor Her'm mm Le mp v UNITED STATES TATENT FFICE.

HERMANN LEMR'OF, LYNN, MASSACHUSETTS, ASSIGNOR To GENERAL ELECTRIC COMPANY,

' A CORPORATION orNEw YORK.

' DOUBLE-TANK FUEL SYSTEM.

Specification of Letters Patent.

Patented May 25, 1909.

T 0 all whom it may concern:

Be it known that I, HERMANN LEMP, aeitizen of the United States, residing at Lynn, county of Essex, State ofMassachusetts, have inventedcertain new. and useful Improvements "in Double-Tank Fuel Systems, of which the following is a specification.

.My invention relates to fuel systems of the double-tank type in which the main tank or source of supply, is preferably at or about atmospheric pressure and fuel is supplied therefrom to the-burner at the desired working pressure by means of a power pump. The fuel in the auxiliary tank, which may or may not be initially supplied from the main tank by gravity feed or otherwise, is'preferably maintained under a pressure suitably higher than that of the atmosphere, but much less than the working ressure, so that fuel will be fed automatical y to the burner, and ata pressure which is suflicient to maintain the flame in a banked condition. Such a system is particularly. applicable to automobiles, in which class of service it is desirable to dispense with a high initial ressure' on the fuel, with its attendant liabi ity to explosion or fire in case of accident or leakage of the system, especially wh'enany of. the more volatile fuels are employed. I

The object of my invention isto provide a simple and convenient means for recharging the auxiliary tank with fuel from time to time as occasion demands.

Hitherto it has been necessary in order to replenish the supply of fuel in the auxiliary tank, first to remove t e pressure on the fuel by allowing the com ressed air to escape from the tank, then to supply the .fuel' in any approved manner, as for example by feeding it from the main tank under gravity, and after the desired quantity has been supplied to again place the tank under pressure, as by means of airsupplied by a hand pump, or furnished from "a reservoir containing compressed air. Manifestly this process? is attended with much inconvenience to the operator, especially when it is necessary to place the tank under the initial pressure by using a manually-operated pump, while on the other hand to employ compressed air necessitates a storage tank which is also objectionable because of the space required to accommod'ate it and also theextra weight. both of which are important considerations in auto-- mobile powersapparatus. With my invention, however, the refilling process is much simplified. In practice I provide a connection extending from the auxiliary tank to the main service pipe at a point between the power pump and the burner, and make use of the pum for recharging the auxiliary tank from t e main source-of sup 'ly. As the pump is capable of delivering fuel at a pressure much higher than that on the auxiliary tank, the air contained in the latter does not have to be released, as the superior pressure due to the pump will force the'fuel into the tank against the pressure of the air therein. This supply connection is controlled preferably by a-valve which is conveniently accessible to the operator, so as to be manipu air may serve as a satisfactory guide to the operator for indicating the quantity of fuel in the auxiliary tank at any given time, in

'- view of the complementary relation existing between the quantity of fuel and the pressure of the air. Thus when the air pressure is indicated to be low the valve in the supply connection may beopened to permit fuel to pass to the tank, and when suflicient fuel has-been supplied to cause the pressure to attain its normal value, as is indicated by the gage, the sup ly may be cut ofi by closing the valve. f for any reason the pressure on the auxiliary tank should become excessive, a portion of the fuel may be drawn off by opening the gravity feed 0011- nection between the mam and auxiliary tanks, thereb causing fuel to flow from the latter to the ormer, b virtue of the relative difference of pressure etween them.

The refilling may be done at any time during operation of the vehicle, but it is better practice to recharge the auxiliary tank when -the conditions of service are such that the pump is not working at its full capacity, as

' draft and is discharged through through the down-draft fine when the load on the vehicle is light and the .demand for'thermal energy is correspondingly reduced. At such times the pump may deliver both to the burner and to the tank without seriously affecting the heating of the boiler. 4

In the accompanying drawing, which illustrates one embodiment of my invention, is diagrammatically shown my improved fuel system in connection with steam power apparatus suitable for automobiles.

Referring to, the drawing, 1 represents conventionally a flash boiler which receives water at the inlet 2 and delivers it as superheated steam to the engine 3, through the pipe at, which is controlled by the throttle 5. In the present case the exhaust steam from the engine is used for inducing a forced the pipe 6 into the down-draft flue 7- w ich connects with the interior-of the casing of the boiler. Situated below the boiler in the bottom of the casing 8 is a' burner 9 which heats the boiler, and the products of combustion pass from the casing either through the up-draft flue 10 when thedemandfor steam is light and the forced draftis not 0 rating; or

1" when 'the apparatus is working and the exhaustlis' in-. ducing a forced draft. I have elected to show a sin leburner'of the jet type, but it is to befunderstood that my'invention is not limited thereto, as another ty e of burner or separate main and auxiliary urners may be used equally well in carrying out the invention in some of its aspects.

Two separate sources of fuel supply are essential to my invention. One of the sources 'is ada ted to supply fuel to the burner at a suitab e pressure above atmosphere, say ten poundsper square inch, which produces a flame of suflicient volume to maintain the boiler in a heated condition, or in other words to support a pilot flame when no steam, or only a small amount, is demanded. The main fuel supply is derived from the other source which is preferably at atmospheric pressure, and by means of a power pump the pressure is increased to about sixty pounds per square inch, which pressure is capable ofv maintaining the main operating flame. The

main tank 11 is situated slightly above the tank 12' in order thatit may supply fuel to pipe 15 is opened so as to permit the air contained in the tank to escape as fuel enters the same through the gravity feed connection'. The fuel is allowed to flow until it has attained the level of the overflow pipe 15 and is seen to overflow and discharge from the cock 16, when the valve l fis immediately closed to cut off the flow from the main tank. Following this the stop-cock of the overflow pipe is closed and the fuel is then placed under air pressure by the air pump.

The main sup 1y of'fuel tot-he burner is delivered throug the pipe 20 by means of the power pump 21. This pump is or may be of the variable stroke type and tends to automatically maintain the fuel supply at substantially constant pressure. The driving mechanism therefor comprises an eccentric 22 which may be mounted on the axle of the automobile or other rotating part and may operate continuously or otherwise as desired. The eccentric is connected to the piston 23 of the pump by a suitable cross-head frame 24 in such a manner as to permit of lost-motion under certain conditions. The eccentric imarts a constant length of stroke .in one direction and operates to move the piston out of the pump cylinder, while 'a suitable elastic means, such for example as springs 25, im art-a stroke in the opposite direction and o a length which may vary as the fuel pressure on-the piston tends to exceed a predetermined amount. The springs are shown fixed atone end relative to the pump cylin frame to move through its full stroke irrespective of the length'of stroke of the piston due to the -action of the springs. These springs are of such strength that a pressure of substantially sixty pounds per square inch may be maintained on the fuel supplied to the burner, and any tendency of the fuel to rise above such pressure is compensated for by their yielding to a greater or less degree so as to alter the effective stroke of the ump. Any equivalent means may be emp oyed for accomplishing this result as my invention is not specifically directed to this feature. It may also be desirable to have-the fixed ends of the pump s rings attached to sin-adjustable device capa le of manipulation from the vehicle seat, wherebythe tension of the springs, and consequently the working pressure due to the pump, may

be varied at will to suit different conditions of service.

The flow of fuel from the auxiliary tank takes place through the pipe 28 which communicates with the main supply pipe, and is controlled by a valve 29. The opening and closing of thisval-ve bears a definite relation to the main fuel supply and to the forced draft; that is to'say, asto the former, it should be opened immediately upon cessation of the main supply, to preserve the continuity of the flame in order to obviate the necessity of relighting, and it should be closed as soon as the engine is started so that fuel will not be shunted relatively to the burner and be delivered to the auxiliary tank. In order to obtain this relationship, I find it convenient to connect the auxiliary supply valve ..with the steam throttle, since, in the present case, the main supply pump is driven by the engine which operates only when the throttle is open. For this purpose-the valve 29 is connected to the throttle 5. by a link 30, or other means, in such relation that as the throttle opens the valve closes, or vice versa. Another important reason for this is, that as the pressure on the burner due to the pump tends to pers st a 'certain'time after the forced draft andithe pump stop, it causes the burner flame to be more or less smoky, due to incomplete combustion with only natural draft, and by opening the auxiliary supply val-ve as soon as the forced draft ceases, the burner pressure may be quickly reduced to that of the auxiliary tankand thereby prevent smoking. Again the burner-would consume more fuel than is necessary if the higher pressure were maintained when the delivery of steam from the boiler ceased. The quantity bf air the auxiliary tank and thereby prevent smokneglecting possible loss due to slight leakage or ,absorption, and hence, after the initial fill ng the hand pump need be seldom if ever, The demand for fuel decalled into service. pends upon the class of service, as to Whether the stops are few or many andlof long-or short duration, for at such time the fire 1s in banked condition and draws its supply from the auxiliary tank. As the quantity'of the fuel decreases, by reason of-this consumption, the pressure on the remaining fuel in the tank, as indicated by the gage, becomes diminished. Hence, by bbserving the pressure gage the operator may ascertain at any time the approximate quantity of fuel in the pressure tank. When coasting, the throttle 5 is closed and the valve 29' open but the pump continues to operate because of its driving connection with the axle. The capacity of the auxiliary tank 12 isso much reater than the displacement of the pump p unge'r, that the pump under these conditions delivers fuel to the burner at substantially the pressure of the tank 12, any surplus fuel flowing into the tank and replenishing its supply after the loss sustained by feeding the burner during standstill. When the pressure falls below normal, it maybe restored by recharging the tank with fuel. This I prefer to do by means of the power pump, and while the vehicle is conditions require. valve diagrammatically, but in practice it moving, preferably at times when the load isv light, as in running on the" level at low speed or coasting down grade. For this purpose I which is adapted to be opened and closed as I have indicated the will be ofsuch construction as to be capable ()f'fllillllPUltltlOIl from the vehicle seat. This enables the operator to open and close the valve at any time without stopping the vehicle or dismounting.

In case the main tank becomes depleted when the vehicle is out on the road and inconvenient to a garage or other place Where fuel can be obtained, the fuel in the auxiliary tank may be employed under such emergency conditions so that the vehicle will not be stalled. For this purpose the fuel in the auxiliary tank can be supplied to the main tank by simply opening the valve 14 in the gravity feed pipe 13 sons to permit the fuel to flow to the main tank by reason of the air pressure in the auxiliary tank. The fuel pump will continue to draw its supply from the main tank as usual.

In accordance with the provisions of the patent statutes, I have described the principle of operation of my invention together with the apparatus which I now consider to represent the'best embodiment thereof; but I desire-to have it understood that the apparatus shown is only illustrative, and that the invention can be carried out by other 'ceive fuel delivered by the pump and to hold it under a pressure lower than that due to the pump, and a controllable connection leading from the receptacle to the burner which connection is normally closed and is adapted to be openedto supply fuel to the burnerto maintain the flame. when the supply of energy for (lllYi-Dg. the pump motor is interrupted. i

2. In a fuel supply system, the con'ibination of a burner, a main supply tank sub-- jected to a low pressure, a pump between the tank and the burner for increasing the pressure of the fuel to service pressure, an auxiliary tank subjected to a pressure above that of the main tank and lower than the normal burner pressure, and arranged to feed: the

burner when the pump pressure falls, and

pump is permitted to discharge fuel from the main to the auxiliary tank for recharging the latter.

3. In a fuel supply system,the combination of a b'urner, a main source of supply at substantially atmospheric pressure, a pump connectedwith thesource and the burner for supplying fuel directly to the latter at high 1 pressure, an auxiliary source of supply connected with the burner for supplying fuel thereto at low pressure, acontrolled connedtion between the sources through which fuel may be fed' by gravity from the main source to the other, and means for. supplying fuel to the auxiliary source from the pump.

4. In a fuel supply system, the combination of a burner, main and auxiliary sources. of fuel supply conneeted with the burner,

means for increasing the fuel pressure be tween the mam source and the burner, a connectlon between said means and the auxiliary source for re-charging said source by said means, and a fuel feed connection between the two sources through which fuel may be fed by gravity from the main to the auxiliary source. 7

5. In a supply system, the combination'of burner, main and auxiliary sources of supply conneeted in parallel relation with the burner, a gravity feed supply pipe between auxiliary tank also connected with the burner, a pump in said supply connection which forces fuel from the main tank to the burner, means for re-charging the auxiliary tank from the pump, and conduits for delivering fuel from the auxiliary tank to the burner and to the main tank, one conduit also being arranged to feed fuel by gravity from the main tank to the auxiliary tank.

. 7. In a fuel supply system, the combination of a burner, a main supply tank con- .nected therewith, a pump for increasing the pressure of the fuel supplied by the tank to the burner, an auxiliary supply tank connected to the burner and subjected to a pressure which is less than the normal burner pressure, means causing the pump to discharge fuel into the auxiliary tank for the purpose of recharging it, and means admitting fuel to the burner from the auxiliary tank when the main supply is interrupted.

8. In a fuel system, the combination of a burner, a main tank, an auxiliary tank under pressure, supply connections between the tanks and burner for delivering fuel to it from either of said tanks, a valved connection between the auxiliary tankand the main 4 supply connection for recharging the tank, and means connecting the two tanks for permitting fuel to flow from one to the other under certain conditions. i

9. In a'fuel supply system, the combination of a burner, a main tank, a supply connection between them, a pump included in the connection for increasing the pressure of the fuel supplied to the burner, arhlauxiliary tank also arranged to supply f e1 to the burner and independently o the main tank, a manually controlled connection between the pump and} theauxiliary tank through which fuel to recharge the tank is forced by said pump, and a valve for controlling the fiow'of fuel between the auxiliary tank and the burner.

, 10. In a fuel supply system, the combination of a burner, a main tank, a pump tending to deliver fuel from the tank to the burner at substantially constant pressure, an auxiliary tank subjected to a pressure greater than that on the main tank and less than the normal pressure on the burner, a controlled connection between the same and the burner, and means for opening communication between the delivery side of the pump and the auxiliary tank to permit the pump to charge said tank, said communication being normally closed or shut ofi".

11.- In a fuel supply system, the combination of'a burner, amain tank, a pump which tends to deliver fuel from the tank to the burnerat substantially constant pressure, an

auxiliary tank connected with the burner,

means for placing the latter tank under airpressure which is greater than the pressure on the main tank and less than the normal pressure on the burner,'means for delivering fuel from the pump to the auxiliary tank to charge said tank, and a valve for controlling the supply of fuel to the auxiliary tank which. is normally closed.

12. In combination, a boiler, a burner "therefor, an engine, a throttle controlling the delivery of steam to the engine, a main source of fuel supply, an auxiliary fuel supply un-' 'der pressure, a pump driven by the engine for delivering fuel from the main source to the burner, two separate-means for supplying fuel to the auxiliary source, one of which conveys fuel from the pump to said source, and means for supplying fuel to the burner from the auxiliary source simultaneously withthe cutting off of steam to the engine.

13., In combination, a boiler, a burner therefor, an engine, a throttle controlling the delivery of steam to the engine, a main source of fuel supply, a pump for delivering fuel from said source to the burner, a regulator for the pump which tends to maintain the delivery of fuel at a constant pressure, an auxiliary tank connected with the burner,

a valve intermediate the auxiliary tank and burner operatively connected with the throttle, and a valved connection between the auxlliary tank and the delivery side of the pump.

14. In combination, a boiler, a burner therefor, an engine, a throttle controlling the delivery of steam to the engine, a main source of fuel supply, a pump driven by, the engine for delivering fuel from said source to the burner, a regulator for the pump which tends to maintain the delivery of fuel at a constant pressure, an auxiliary. tank connected with the burner, a valve intermediale the auxiliary tank and the burner operatively connected with the throttle, a gravity feed-pipe between the main tank and auxiliary tank, a valve therefor, a connection between the auxiliary tank and the delivery. side of the pump for permitting the pump to charge said tank, and means for regulating the flow of fuel through said connection.

15. In a fuel supply system for automobiles, the combination of a burner, main and auxiliary sources of fuel supply which are adapted to supply fuel independently to'the burner, a power pump arranged between the main source and the burner'which while the automobile is running, is adapted to operate and supply fuel to the burner, a connection between the discharge side of the pump and the auxiliary source for recharging the latter from the pump while it is in operation, and a manuallyopera ted valve for controlling said connection.

16. In a fuel supply system for automobil s, the combination of a steam or other vapor generator, an engine for driving the vehicle, a burner for heating the generator,[

main and auxiliary sources of fuel supply separately connected with and delivering fuel to the" burner, a pump driven by the engine which supplies fuel from the main source-to the burner, a connection between the delivery side of the pump and the auxiliary source which is adapted to convey fuel from. the pump to the source for recharging, and a manually operated controlling -:valve in said connection. 1

17. In a fuel supply system for automobiles, the combination of a steam or other vapor generatonan engine for. driving the 4 vehicle, a throttle for controlling the supply of vapor to the-engine, a burner for heating the generator, main and auxiliary sources of fuel supply connected with the burner to supply the same, a pump driven by the engine which supplies fuel from the maln source to the burner, a supply connection be- 'tween the delivery side of the pump and the auxiliary source for refilling the latter from the pump, a manuallycontrolled valve controlling-said connection,- a valve for controlling the supply of fuel between the auxiliary tank and the burner, and means for simul- -the engine which supplies fuel from the main source to the burner, means for main taining the delivery of the pump at substantially constant pressure, a connection between the delivery side of the pump and the auxiliary source for refilling the latter from the pump, a manually controlled valve controlling said'connection, a valve for controlling the supply of fuel between the auxiliary tank and the burner, and "means for while closin the throttle or vice versa.

19. In a fuel supply system for automobiles, the combination of a steam or other vapor generator, an engine for driving the vehicle, a throttle for controlling the supply of vapor to the engine, a burner for heating the generator, main and auxiliary sources of fuel supply connected to the burner, a pump driven by the. engine which supplies fuel from the main source to the burner, a variable stroke mechanism for the pump for maintaining the delivery thereof at substantially constant pressure, a connection between the deliver side of the pump and the auxiliary source or refilling the latter from the pump, a manually controlled valve controlling said connection, a valve for controlling the supply of fuel between the auxiliary tank and the burner, and means for simultaneously opening the said latter valve while closing the throttle or vice versa.

20. In a fuel supply system, the combi nation of a boiler, a burner for heating the boiler, an engine receiving steam from the boiler, a throttle valve for controlling the supply of steam from the boiler 'to the engine, a main fuel supply tank, a fuel pump driven from the engine, a supply conduit between the main tank and the pump, a delivery conduit between the pump and the burner, a valve in said delivery conduit adjacent the burner, an auxiliary tank arranged at a lower level than the main tank, a conduit'extending between the two tanks for feeding fuel bygravity fromthe mam to the auxiliary tank, a valve in said feeding conduit, a conduit leading from the delivery conduit at a oint between. the pump and the valve in sald conduit to the auxiliary tank for re-charging said tank with fuel under pressure from the pump, a manually controlledvalve in the re-charging conduit, a conduit for supplying fuel from the auxiliary tank to the delivery conduit at a simultaneously opening the said latter valve point between the pump and the valve in my hand this twenty-eighthday of J uly, said delivery conduit, a valve in the last 1904. mentioned conduit, and a connection between said valve and the throttle valve HERMANN LEMP' 5 which opens said valve when the throttle I Witnesses: v valve is closed and vice versa. DUGALD MoK. McKILLo1 In witness whereof, I have hereuntoset JOHN A. MCMANUS. 

